I just had to replace a leaking one on a 69 with a 427, the hole is to the outside of the head (This is still the backside of head) toward power brake booster and the bracket mounts like an upside down "L" when looking from side and is straight across. The steel copper plated line has to be bent (as it comes straight) to provide Z-bar clearence and to line up with bracket. My bend looked like an elongated "S" (going from block adaptor to bracket on head). The bracket is where the junction is mounted and the plastic oil lin from gauge mounts to top of junction, the steel cooper plated line meets junction from bottom. Sorry there is no way to get a camera in their to take a pic (Big Block=no room). Hope this helped.

Sorry I couldn't remember upper or lower hole but this should show itself. The 69 I just did had headers so I took off the header and had plenty of room and did work from below. If you got stock exhaust I think it will be a lot harder and probable have to do it from above (I could be wrong). GOOD LUCK and let me know how it works out.